RB, John has been posting a considerable amount of research on this topic to this forum for over a year, and has published an article outlining his arguments in more detail. I'd consider his work "serious research," but you may want to review his published work before you make up your mind. (See above for details on how to get one.)

Personally, I'm rooting for WV :) But I really feel that the story of John Henry is probably fiction or mostly fiction, but a great song. Man/animal vs. machine was a common theme of the era, and it still resonates with us today.